Higher LDL cholesterol levels in the plasma increase cardiovascular risk and reduction in the levels of LDL would decrease CVD risk by a comparable percentage (PNAS, 2009, 106, 9546-9547). Clearance of LDL cholesterol from plasma is through the action of LDL receptors in the liver and LDL receptors are cell surface glycoproteins that bind to apoliporpotein B100 (apoB 100) on LDL particles with high affinity and mediate their endocytic uptake (Journal of Biological Chemistry, 2009, 284, 10561-10570). Defect in hepatic cholesterol clearance and elevated levels of plasma LDL cholesterol that result from the mutations cause familial hypercholesterolemia. Such mutations are identified in the human LDL receptor and later in apolipoprotein-B (Nature Structural and Molecular Biology, 2007, 14, 413-419). Recently, mutations within certain subtypes of the pro-protein convertase subtilisin/gene such as the subtype nine (hereinafter “the gene”) were found to represent a third class of mutations associated with autosomal dominant hypercholesterolemia (ADH). The discovery, etiology and functions of this subtype gene is discussed in details in Nature Genetics, 2003, 34, 154-156, Trends in Biochemical Sciences, 2008, 33, 426-434 etc. Several missense mutations (S127R, D129G, F216L, D374H, D374Y) are associated with hypercholesterolemia and premature atherosclerosis (J Lipid Res. 2008, 49, 1333-1343). Loss-of-function mutations (R46L, L253F, A433T) lead to elevated receptor abundance, enhancing clearance of LDL cholesterol from the circulation and reducing cardiovascular risk (Nature Structural and Molecular Biology, 2007, 14, 413-419).
Detailed molecular mechanisms explaining the association of LDLR and the particular subtype gene and LDLR degradation is not very clear (Drug News Perspectives, 2008, 21, 323-330). Because of inhibition of LDLR recycling, number of LDL receptors on the cell surface are decreased and this increases plasma LDL levels (PNAS, 2009, 106, 9546-9547).
Various approaches for inhibiting this particular subtype gene are reported, including gene silencing by siRNA or antisense oligonucleotides, mAb disrupting protein-protein interactions or by peptides; all the above-mentioned strategies have shown lowering of LDL cholesterol which may be effective therapy for treating hypercholesterolemia (Biochemical Journal, 2009, 419, 577-584; PNAS, 2008, 105, 11915-11920; Journal of Lipid Research, 2007, 48, 763-767; PNAS, 2009, 106, 9820-9825). However, very little success has been reported in trying to inhibit this subtype gene by using small molecules. Such small molecule inhibitors has its obvious clinical and therapeutic benefit over the other approaches as discussed above. We herein disclose novel small molecules which have shown to inhibit this particular gene in in-vitro studies and therefore provides an alternate beneficial approach for treating patients in need of such therapy.